Abstract
As the fundamental study for designing computer user interfaces, workload imposed by keeping short term memory is studied. Two experiments with using personal computers were conducted. Workloads caused by two different strategies of keeping short term memory were compared in the first experiment, and it turned out that positive strategy shows less workload than the strategy of only rehearsal. Second experiment treats the relation between the workload and chunks. It turned out that perfect recall is to be expected under five chunks and that the workload will be worse over five chunks. It also turned out that workload is not in the same level even under the five chunks.
